Eczema

Eczema is not really a single disease of the skin. Rather,
"eczema" is a generic name for a particular kind of skin
reaction where you see itching, fluid weeping or oozing
from the rash, and lichenification (skin thickening
where the normal fine lines on the skin surface become
deeper and stand out more).

Like other diseases, eczema
can be acute (happening relatively suddenly) or chronic
(happening for a long time). Acute eczema usually comes
with redness, oozing and weeping, and microscopic vesicles
(fluid-filled pockets) in the epidermis (the outermost layer of
our skin). Chronically eczematous skin is usually thickened, scaly,
and dry; the skin colour may change (lighter or
darker), and lichenification may be more severe. Eczema is
often an allergic reaction to something that contacts the skin,
and people with eczema also tend to have
allergic rhinitis,
asthma, or both.

The term "eczema" is generic: there are several different
varieties, with different causes, different appearance, and
sometimes different treatments.

As the name suggests, contact dermatitis is caused by noxious
things coming in contact with the skin. The skin injury may
be irritant (resulting from direct chemical or mechanical
damage to the skin) or allergic (caused by an allergic reaction
to something that contacts the skin).
The two kinds are not entirely separate -- the main difference
is that allergic reactions occur mainly in those people who have
become allergic to the substance they touch, while irritants are
irritating to just about everyone who touches them. That's not
much of a difference: the oils produced by
poison ivy, poison
oak, and poison sumac are technically allergens, but you become
sensitive to them so quickly that they might as well be irritants.

Irritant-based contact dermatitis is more common than
allergic-based, especially in children. Lots of things
can irritate the skin, including:

Saliva.

This is probably the irritant I see most often
in babies. The combination of saliva and
(partly-digested) formula or milk that babies spit up
and drool seems to be especially irritating to skin,
and drooling while asleep makes things worse since the
drool ends up on the bedclothes where it sits in contact
with the baby's cheek. The solution to this that I prefer
is to keep the baby's face clean at all times and change
the bedclothes as soon as you notice any drool on them.
(And I will be the first to admit that this may be nearly
impossible, practically speaking.)

Soaps, detergents, fabric softeners, bubble baths,
perfumes...

Babies are especially sensitive to chemical irritants,
and sometimes even the slight residue from detergents
and fabric softeners will lead to irritation. Dryer-sheet
softeners are especially notorious in this regard; even
if you are not using them on the baby's clothes, if you
use dryer sheets on your own clothes the sheets leave a
residue on the inside of the dryer which then comes off
on the baby's wash in the next load (the residue can
persist for several loads after the sheets are used, as
a matter of fact). The solution is to avoid all
potential irritants; this means that you may not be able
to use dryer sheets for any laundry in your dryer.

Although these are three different plants, the oils they
produce have just about the same (nasty) effect, and once you
become sensitive to one you are sensitive to all of them.
As I mentioned above, these are technically allergens, since
you have to become sensitive to them before your skin reacts.
However, it takes a very short time to become sensitive
to these oils. Another nasty thing about the oils is that
they are not easy to remove from your skin -- soap and water
can spread them to other parts of your body if you're not
careful -- and they will also stick to clothes and other
things, then come off on your skin some time after you've
left the plants behind.

Atopic dermatitis, practically speaking, is a dermatitis whose
cause is not known. Often it appears along with contact dermatitis,
but persists long after you've eliminated every possible allergen and
irritant. Often atopic dermatitis appears as unusually dry skin.
Mild atopic dermatitis and contact dermatitis can be aggravated by
anything that dries out the skin -- including cold weather, and
including soap and water. And, although atopic dermatitis can appear
without other allergy problems, it often occurs in children who later develop
asthma or
respiratory allergies.

Mild cases of atopic dermatitis can often be treated
with just a good moisturizing hand or body lotion. The "greasier"
lotions often work better: washing with soap and water removes dirt
from your skin, but also removes the natural oils from your skin and
makes it drier. Some people are so sensitive to dry skin that they
must apply lotion to their entire body right after each bath or
shower, before the water left on their skin dries out (water actually
dries skin out very quickly as it evaporates; that's why you need to
replenish the oils as well). Compulsive hand-washers -- including
doctors, nurses, and other health-care workers -- often have dry-skin
problems that approach that of people with atopic dermatitis. My own
hands often crack and sometimes bleed by the end of a day in the
office or hospital, which isn't surprising since I may have to wash
my hands 50-100 times on a busy day; I usually apply a good, greasy
hand lotion (such as Eucerin® or
Aveeno®), or both an ordinary hand
lotion and Vaseline®, to my
hands at bedtime just to replenish all the natural oils I've washed
out of my hands during the day.

For more severe atopic dermatitis, we sometimes have to resort to
steroid treatment. Usually we start with mild "topical" (applied
to the skin) steroid creams or lotions -- so mild that they can be
bought over-the-counter without a prescription -- and in many cases
that's all that is needed. (I do suggest to my patients, and to you,
that you not use even over-the-counter steroids without talking to
your doctor first. Even the over-the-counter steroids can be
hazardous, especially if you don't use them properly.) If the OTC
steroids don't work, we may then suggest more potent topical
steroids, which do have to be prescribed by your doctor. Sometimes
-- very rarely -- a patient may need oral steroids; I usually
send patients of mine who need oral or the very strong topical
steroids to a dermatologist. One possible side effect of using
topical steroids for a long time, especially on the face, is atrophy
of skin tissue; therefore, we try to avoid long-term topical steroids
whenever we can, using them only for bad flare-ups.

Really bad atopic dermatitis may not respond very well to
steroids. Some of these patients respond to tacrolimus, a
medicine originally developed to treat certain kinds of cancer,
or pimecrolimus, which is similar to tacrolimus but was
intended mainly for treatment of severe eczema. Like all cancer
drugs, tacrolimus and pimecrolimus have potential side effects, and
we do not prescribe these medications unless everything else fails.

Contact dermatitis can sometimes be treated the same way we treat
atopic dermatitis. First, though, you need to identify the
irritant or allergen and get it away from you -- it's always
better to remove the cause of a rash than to use medicines to get
rid of the rash. In most cases removing the irritant is all the
treatment you need.

PLEASE NOTE: As with all of this Web site, I try to give
general answers to common questions my patients and their parents ask me
in my (real) office. If you have specific questions about your
child you must ask your child's regular doctor. No doctor can give
completely accurate advice about a particular child without knowing and
examining that child. I will be happy to try and answer
general questions
about children's health, but unless your child is a regular patient of
mine I cannot give you specific advice.